episode40

040 The Role of Hair Cells in Hearing

Leslie Samuel IBTV, Physiology, Sense Organs 78 Comments

Do you ever wonder what happens to the hair cells inside our ears as we hear sound? What role do these tiny hairs have in hearing?

Watch this short movie as Leslie explains clearly and vividly enough for us to understand the main role of these tiny hair cells as sound enters our ears.

Enjoy!

Transcript of Today’s Episode

Hello and welcome to another episode of Interactive Biology TV where we’re making Biology fun!  My name is Leslie Samuel and in this episode, Episode 40, I’m going to talk about the role of hair cells in hearing. So, let’s get right into it.

In Episode 39, we looked inside the cochlea to see what happened in response to sound. What we said was, in response to sound, the basilar membrane vibrated up and down, and this is the basilar membrane, which causes the Organ of Corti, which is this section here, to vibrate up and down, causing the tectorial membrane to move in a windshield wiper-like fashion that causes these hair cells to bend, the stereocilia, and the hair cells bend, causing a signal in the auditory nerve that then goes to the brain.  The brain says, “Okay that is sound,” and you hear it.

What we’re going to do today is we’re going to look specifically at what happens inside these hair cells, specially the inner hair cells which are directly responsible for the signal being sent to the brain that results in the sound that you are hearing.

So, let’s look at what happens inside those hair cells.  All right, so, I’m going to draw a hair cell.  Let’s say this is my hair cell right here. On the hair cell, I have stereocilia.  Now, this stereocilia occur in pairs: we have a long one and a short one.  In the short one, we have potassium channels so, that’s the potassium channel right here.   But, what’s interesting is that the long hair cell is mechanically connected to the short hair cell via that gate. Now, as you can imagine, when the tectorial membrane moves down on this hair cell, that causes the hair cell to bend.  So, let’s say this hair cell, the long hair cell, bends in that direction.  What is that going to do to these channels?  That’s going to cause these channels to open.  Now, these channels are mechanically-gated potassium channels.  They’re not extremely selective to potassium but, for this purpose, we’re going to look at what it does with the potassium ions.

Now, in the fluid that’s surrounding these stereocilia, we have endolymph. An endolymph is very rich in potassium ions.  So, let’s say we have potassium ions, K+, all around here.  When these mechanically-gated channels open, that is going to cause potassium ions to flow into the hair cells.  What is that going to do to the membrane potential (Em) ?  That is going to increase the membrane potential. Once the membrane potential increases, something else happens.  We have calcium ions that are also outside the cell. When that membrane potential increases, potassium is in here that’s going to cause calcium channels, voltage-gated calcium channels to open and calcium is going to rush into the cell.

Now, if you can remember when we spoke about neurotransmitter release, we said that calcium ions are the trigger that causes the neurotransmitter release in axon terminals.  This is the exact same thing that happens.  We have neurotransmitters in vesicles here and those neurotransmitters are then going to be released, and as I showed in the previous picture, this is connected to the auditory nerve, and that sends signals to the brain.

That’s all the content for this video.  I hope you learned a lot.  If you have any questions, go ahead and leave them in the comments below. That’s it for now, and I’ll see you in the next one.

82 comments
Cic
Cic

Hi! Thank you so much! This helped me understand the IHC more than my textbook had. I would second in asking for a video on the vestibular system, if theses are still running. It would be fantastic! Thanks, again!!

Leeann Gooding
Leeann Gooding

omg thank you so much for this video....i kept reading that k+ gates open and cell is depolarized and i couldnt understand why but its because endolymph is rich in K+ so gradient is higher outside cell ....thank you thank you

Sreelakshmi V A
Sreelakshmi V A

Can you explain what happens in tectorial membrane in response to the vibrations in organ of corti???

Kin Shek
Kin Shek

As a patient of labyrinthitis, been dizzy for 24/7 for a year Now. Could you explain the hair cells in semi circular canals and the importance for balance and sense of space. Thx

scarletwomannedm
scarletwomannedm

As a student getting ready to take my state board exam for Cosmetology this is a fascinating mini-lecture. All of your videos have helped me to understand anatomy and biology better (especially the parts on the Integumentary System--which for the Cosmetology field is obviously the most important to be studying and understanding) They have kept me interested and you made it fun! Great job!!

the7real7deal
the7real7deal

The best series of Anatomy and Physiology videos on the internet.

rmalinak07
rmalinak07

These were the most helpful series of videos on the subject on youtube. thank you!

TshegoTT
TshegoTT

Does anyone know where I can get a video/article which clearly explains how outer hair cells help generate otoacoustic emissions (OAEs) and/or how the reflection of incoming waves occur? Thank you.

TshegoTT
TshegoTT

Thank you very much for the video. Please make a video on the relation between the outer hair cells and otoacoustic emissions (or just the generation of otoacoustic emissions in general). Thank you.

green5sing
green5sing

Thank you so much! I was so lost in my Audiology class until I watched your videos (36-40)! You do such an awesome job of explaining things so that people can understand it!

green5sing
green5sing

Thank you so much! I was so lost in my Audiology class until I watched your videos (36-40)! You do such an awesome job of explaining things so that people can understand it!

kmac0258
kmac0258

I really enjoy these and they really help me to learn. is there a possibility of him continuing the senses and doing taste and smell too?

SpeedySpod
SpeedySpod

what's the neurotransmitter? Possibly glutamate and 'unknown substance' - would you happen to know???

SpeedySpod
SpeedySpod

what's the neurotransmitter? Possibly glutamate and 'unknown substance' - would you happen to know???

Adriana
Adriana

loved it, it would be good if you did something about vestibular system too. from Portugal!

ilselpz
ilselpz

sir i love you. i think i am finally getting this !

ilselpz
ilselpz

sir i love you. i think i am finally getting this !

rita silva
rita silva

Is this the last video on audition?

rita silva
rita silva

Is this the last video on audition?

rita silva
rita silva

Is this the last video on audition?

20019988
20019988

Great video very simple illustration

20019988
20019988

Great video very simple illustration

215196
215196

can you tell me what is the different between inner hair cell and outer hair cell?

215196
215196

can you tell me what is the different between inner hair cell and outer hair cell?

InteractiveBiology
InteractiveBiology

Unfortunately, Leslie is unavailable to take questions as he has no time to help. In the meantime, you can go to our FB fan page, post your questions, and your fellow readers, followers, and fellow enthusiasts in Biology may find time to answer them.

InteractiveBiology
InteractiveBiology

@Djalitana Unfortunately, Leslie is unavailable to take questions as he has no time to help. In the meantime, you can go to our FB fan page, post your questions, and your fellow readers, followers, and fellow enthusiasts in Biology may find time to answer them.

InteractiveBiology
InteractiveBiology

@Djalitana Unfortunately, Leslie is unavailable to take questions as he has no time to help. In the meantime, you can go to our FB fan page, post your questions, and your fellow readers, followers, and fellow enthusiasts in Biology may find time to answer them.

InteractiveBiology
InteractiveBiology

Unfortunately, Leslie is unavailable to take questions as he has no time to help. In the meantime, you can go to our FB fan page, post your questions, and your fellow readers, followers, and fellow enthusiasts in Biology may find time to answer them.

Djalitana
Djalitana

second watch answered my question, without calcium ions no neurotransmitter release. the ability of the hair cells in transmission of sound is varies according to their distance to the auditory nerve? thanks

Djalitana
Djalitana

second watch answered my question, without calcium ions no neurotransmitter release. the ability of the hair cells in transmission of sound is varies according to their distance to the auditory nerve? thanks

Djalitana
Djalitana

second watch answered my question, without calcium ions no neurotransmitter release. the ability of the hair cells in transmission of sound is varies according to their distance to the auditory nerve? thanks

InteractiveBiology
InteractiveBiology

Thank you for your interest in our Biology videos. Unfortunately, Leslie is too busy at the moment to answer any Specific Biology questions. He has many to work on, so stay tuned for more.

InteractiveBiology
InteractiveBiology

Thank you so much. We have more videos coming very soon, so please stay tuned!

InteractiveBiology
InteractiveBiology

@Djalitana Thank you for your interest in our Biology videos. Unfortunately, Leslie is too busy at the moment to answer any Specific Biology questions. He has many to work on, so stay tuned for more.

InteractiveBiology
InteractiveBiology

@Djalitana Thank you for your interest in our Biology videos. Unfortunately, Leslie is too busy at the moment to answer any Specific Biology questions. He has many to work on, so stay tuned for more.

InteractiveBiology
InteractiveBiology

Thank you for your interest in our Biology videos. Unfortunately, Leslie is too busy at the moment to answer any Specific Biology questions. He has many to work on, so stay tuned for more.

InteractiveBiology
InteractiveBiology

@LittleDanzig Thank you so much. We have more videos coming very soon, so please stay tuned!

InteractiveBiology
InteractiveBiology

@LittleDanzig Thank you so much. We have more videos coming very soon, so please stay tuned!

InteractiveBiology
InteractiveBiology

Thank you so much. We have more videos coming very soon, so please stay tuned!

Eric Humphries
Eric Humphries

I'm learning a lot from these lessons! My teacher's lectures + your lecture = better understanding! Don't ever cease to strive for increasing your communication talent! Simplicity is key!

LittleDanzig
LittleDanzig

I'm learning a lot from these lessons! My teacher's lectures + your lecture = better understanding! Don't ever cease to strive for increasing your communication talent! Simplicity is key!

LittleDanzig
LittleDanzig

I'm learning a lot from these lessons! My teacher's lectures + your lecture = better understanding! Don't ever cease to strive for increasing your communication talent! Simplicity is key!

LittleDanzig
LittleDanzig

I'm learning a lot from these lessons! My teacher's lectures + your lecture = better understanding! Don't ever cease to strive for increasing your communication talent! Simplicity is key!

Leslie Samuel
Leslie Samuel

Hi, I'd love to but unfortunately I'm no longer able to take different requests.